MELBOURNE, Australia — Alex Michelsen humorously mentioned that a lengthy chat with his mother back in California had to be cut short due to his busy schedule at the Australian Open on Saturday morning. His excuse for the brief conversation was quite justifiable: the 20-year-old tennis star had just secured a 6-3, 7-6 (5), 6-2 win against No. 19 seed Karen Khachanov.

This impressive victory marked Michelsen’s advancement to the fourth round of a Grand Slam event for the first time, and notably, it was his second top-20 ranked opponent he had overcome within the week, having previously defeated No. 11 Stefanos Tsitsipas in the first round.

During his post-match interview at John Cain Arena, Michelsen addressed his mother with a smile, saying, “Mom, hi! I’m sorry I only called you for a minute this morning. I had things to do. I love you. I miss you. I hope everything’s good at home.”

Michelsen is set to face No. 8 seed Alex de Minaur from Australia in the quest for a quarterfinal berth. De Minaur secured his place by winning against No. 31 Francisco Cerúndolo later on Saturday with a score of 5-7, 7-6 (3), 6-3, 6-3.

Additionally, Michelsen has achieved a notable milestone as he is now the second-youngest American male to reach this stage at the Australian Open since Andy Roddick accomplished the feat in 2003. Two years prior, Ben Shelton had been roughly a month and a half younger than Michelsen at this point in the tournament.

Michelsen is among a promising group of American tennis players making significant strides at Melbourne Park, with six American men and five women progressing to the third round—marking a record for the tournament.

His victories have come against opponents who have made a considerable impact at this hard-court event. Tsitsipas was the 2023 Australian Open runner-up, while Khachanov advanced to the semifinals that same year.

Coached by Robby Ginepri, a semifinalist at the 2005 U.S. Open, Michelsen displayed remarkable skill, converting all four break points he had against Khachanov. He also delivered an impressive performance with a total of 39 winners compared to 27 unforced errors.

“I played unbelievable most of that match. I don’t know what’s going on. … I’ve never hit my forehand that well,” Michelsen commented on his performance. “I played some of my best tennis at the end.”